Device and method for electrically contacting treatment material in electroplating systems

ABSTRACT

The subject matter is directed to electrical contacting of band- or plate-shaped materials ( 1 ), which are conveyed by transport track through an electroplating system. The cathodically polarized contact means ( 6 ) may be located on the underside of the material ( 1 ) in the electrolyte ( 12 ) circulated in the electroplating system. The material is electrically contacted to transfer current to the material ( 1 ). Each tubular contact means ( 6 ) is cooled by means of a cooling unit or a cooling medium. No metal is deposited on the cooled surface of the contact means ( 6 ) if the temperature difference between the working temperature of the electrolyte ( 12 ) and the surface temperature of the contact means ( 6 ) is sufficiently large. This property can be supplemented with a surface of the contact means ( 6 ) that cannot be cathodically metal-coated in the electrolyte ( 12 ) used.

The invention relates to the electrical contacting of material to be electroplated in electroplating systems. Wet chemical systems suitable for this purpose include immersion bath systems, drum systems, continuous flow systems and systems for roll to roll tape-shaped material, as well as other electroplating equipment. The material to be electroplated includes piece material, plate-shaped material, films and tapes made, for example, of metal, plastic, ceramic, glass and other substances that are at least partially electrically conductive on the surface. Examples include metal work pieces, circuit boards or conductor films, wafers and solar cells.

The entire area or structured area of the electrically conductive surfaces of the material to be electrochemically treated using the methods of the invention must be cathodically arranged in an electrolyte along with an anode. This requires the use of at least a rectifier or pulse rectifier, whose negative pole is connected to the surface of the material to be treated, and its positive pole is connected to the anode of at least one electrically conductive electrolytic cell.

In immersion plating, the cathodic material is in electrical contact with, for example, frames and material carriers by means of contacts. In continuous flow plating, the material is in continuous or discontinuous electrical contact with rotating or clamping means of conveyance. In roll to roll plating, for example, contact rollers establish the electrical contact. Because of their cathodic polarity, these means of contact and/or conveyance are electroplated almost like the surface of the material itself. This metalization of the means of contact in all the various types of electroplating is very problematic. The means of contact must be continuously de-metalized. Several solutions are already known for this purpose. The frame contacts attached to the material carriers in cyclically operating immersion plating systems must be de-metalized at regular intervals in special processes. Though this de-metalization does not present any particular technical challenge, it is economically very disadvantageous. In the case of continuous flow systems, the means of contact must be detached during continuous electroplating. Proven technical solutions are already known to meet these technical challenges.

According to the prior art, the electrical means of contact are de-metalized electrochemically, i.e. etched. For this purpose, they are connected anodically. In order that the means of contact themselves are not etched, they must, at least on their surface, be made of an anodic material that is resistant to the electrolyte used.

The surface of anodic resistant metals such as titanium, niobium or tantalum oxidizes in the most commonly used acidic electrolytes. These thin oxide films are electrical insulators. In practice, electrical conductivity or contacting is achieved via the remaining pores in the oxide layer and by applying pressure and/or friction to the contact partners. The application of pressure or friction through the contacts on the material is not possible in the case of sensitive material, such as glass. In order to prevent the breakage of such material, rolling contacts and other rotating means of conveyance may be used to apply only small forces on the material. This means that metals with an oxidizing surface are almost completely excluded for use as the means of contact. Non-oxidizing materials, such as precious metals, are required here for the coating of the means of contact.

Practice also shows that metals that have had oxidized surfaces or metal oxide layers deposited on them can only be subject to incomplete electrolytic demetalization. Residues of the metalization remain as particles adhering to the oxide layer. Therefore, the surfaces of these means of contact are also provided with a precious metal coating. This eliminates the problem of the insulating oxide layer.

However, it is technically very difficult, if not impossible, to plate the oxidizing metal of the contacts in such a way as to be permanently adherent and wear-resistant. In practice, such contacts have to roll on, for example, sharp-edged circuit boards. The result is rapid wearing of the precious metal coating, whereby the efficiency of the entire flow system is reduced.

Where fragile material has to be electrochemically treated, such as glass discs, hard metallic means of conveyance and contact are almost incapable of being used. At least the surface of the means of conveyance and/or contact needs to have elastic materials. The means of contact must also be electrically conductive. According to the prior art, this can be achieved through a metal/plastic composite that offers sufficiently good electrical conductivity, particularly when the composite material is locally compressed in the temporary contact area.

The conductivity is achieved through chemically and electrochemically stable metal particles or carbon particles that are incorporated, for example, in elastomers or rubber. The object of the invention is to provide an equipment and method which permit the electrical contacting of a material to be electroplated in electroplating systems of all kinds by means of simple static or rotating contacts, whereby these contacts are not metalized by avoiding the disadvantages of the prior art. By the surfaces to be electroplated is meant the entire surface or structured surfaces. The structures can be formed by means of a resist on an electrically conductive seed layer or, for example, by a printed electrically conductive circuit pattern as a seed layer on an insulated substrate.

The object is achieved by the devices according to patent claims 1 and 7 and by the method according to patent claims 4 and 10. Possible additions and combinations of the invention are described in the dependent claims.

The means of contact consist of static or rotating contacts. Static contact means contacting the material, for example, in immersion systems. Rotating contact wheels or contact rollers in continuous flow systems contact the goods on at least one contact track, or transversely in the direction of conveyance over the entire width of the material. The hard or elastic contact wheels or contact rollers are electrically conductive on their surface at least on their rolling circumference. Only a small part of the rotary means of contact according to the invention is located temporarily in the area of the electrolytic cell, i.e. in the area of the electric field that exists between the soluble or insoluble anode and the material to be electroplated as the cathode. The remaining area of the cathodic means of contact and contact wheels or contact rollers is shielded from the electric field of the electrolytic cell(s) by means of electrically non-conductive shields. The contact means are not metalized in the area of the shielding. Therefore, only a small part of a contact wheel or a contact roller can be continuously electroplated, i.e. that part which is close to the cathodic material and thus lies within the electrolytic cell and its electric field.

In the case of the static means of contact of, for example, frames in immersion bath systems or contact tracks of sliding contacts as well as clamp contacts in continuous flow systems, the same area that electrically contacts the goods is always exposed to the electric field of the electrolytic cell. This area of the means of contact that is exposed to the electric field of the electrolytic cell, can be metalized like the material itself.

These electroplating difficulties can be avoided in a first model of the invention by cooling the contact means and, in a second model, by using a contact-making material, which does not lead to electrochemical metalization in the electrolyte used.

The electrolyte in question is required to be at a specific operating temperature for electrochemical deposition, especially for adhesion and proper electroplating. Below this working temperature, either the metal deposited is industrially unusable, or there is no deposition at all. As the difference between the working temperature of the electrolyte and the surface temperature of the means of contact increases, the deposition decreases or there is no deposition at all. In practice, the working temperature of the electrolyte is typically between 30° C. to 80° C. The temperature of a conventional liquid cooling medium is, for example, 8° C. Even lower temperatures can be obtained with conventional cooling devices such as compressors, evaporators, heat exchangers Peltier elements etc. Thus, a sufficiently large difference can be obtained between the working temperature of the electrolyte and the surface temperature of the means of contact, by means of which there is no deposition of metal on the cathodic surface of the means of contact.

Electrochemical plating is not possible for all materials and electrically conductive surfaces with a given electrolyte. This fact is used in the additional model of the invention. At least the electrically non-insulated surfaces of the cathodic means of contact are made of such a non-metalizable material. An example is a means of contact consisting of tin or niobium at least on the surface. These are, for example, not metalized electrochemically in a hard chrome bath.

In addition, a combination of contact cooling and an un- or almost un-metalizable material in the electrolyte in question at the selected operating temperature of the electrolyte is possible according to the invention.

In all cases, the electroplating material is electrically contacted, whereby the contacts are not permanently metalized and, therefore, do not need to be de-metalized separately. Thus, anodically etched polarity of the means of contact is not required.

The fact that the means of contact according to the invention do not need to be polarized anodically, but are instead constantly connected in a cathodical manner for the electroplating process, means that electrically conductive materials or similar fillers can also be used for this if they are chemically stable in the electrolyte but not electrochemically stable. Such materials, such as stainless steel, are considerably cheaper than the other stable anodic metals such as titanium, niobium or tantalum. In a sulfuric acid copper electrolyte, a suitable stainless steel is, for example, the one with the trade name Hastelloy C. These materials can also be processed more economically than the aforementioned electrochemically resistant metals. An additional advantage is that, for example, stainless steel in the electrolyte usually does not form a problematic insulating oxide layer on the surface of the contacts of, for example, the galvanic aggregate or on the running surface of the contact wheels or on the sliding surface of the sliding contacts. Therefore, when compared to oxidizing metals, this results in a much smaller electrical transition resistance at the contact point. It is therefore heated to a lesser extent, which provides protection both for the material as well as the means of contact, i.e. more gentle as far as wear is concerned. Good electrical contact of essentially non-oxidizing materials on the means of contact also requires a smaller contact force, thereby avoiding, for example, deformation or embossing, especially of films even when using hard means of contact. The same applies to the internal connections of the electrically conductive particles of the fillers within elastic composite materials. Small contact transition resistances of the fillers with respect to the material also occur in the case of these elastic means of contact.

In the case of particularly aggressive electrolytes, it may happen that the available non-oxidizing material for the contact wheels is not sufficiently chemically stable. In this case, the means of contact are provided with an electrically conductive protective layer at least at the contacting surface. A coating with an electrically conductive diamond layer in addition to precious metals is especially suitable for this purpose, which is also particularly resistant to mechanical abrasion. The conductivity of, for example, a 5 μm to 10 μm thick diamond layer is produced by doping, for example, with boron. The surface of contacts coated in this manner is similar to metallic contact materials. Their electrochemical metalization is avoided by means of contact cooling according to the invention and/or with an electrolyte in which no metal can be deposited on a diamond coating. In contrast to a possible precious metal coating, the diamond coating is extremely resistant to abrasion and wear. These properties are a major added advantage, especially for the rotating or sliding contacts according to the invention in continuous flow plating systems.

Of course, diamond coating is also suitable for oxidizing materials, such as titanium. Contact wheels and contact rollers made of stainless steel with or without a diamond coating are preferable when implementing the invention.

The effectiveness of the invention, namely the avoidance of permanent metalization on the means of contact may, if required and in particular when the working temperature of the electrolyte is close to ambient temperature, be increased by combining with electroless chemical etching. As an etchant, the electrolyte of the electrolytic cell or of the working container in which the plating is carried out can be used. In many plating baths, the electrolyte used with respect to the deposited metal has a re-dissolving effect, i.e. an etching property, as is the case with copper electrolyte based on sulfuric acid. This property is used according to the invention for complementary de-metalization of the means of contact when the cooling thereof or the choice of the electrolyte, are not sufficient, i.e. when there is a slight deposition of the metal on the cooled means of contact.

The electrolyte is supplied during electroplating by circulation through the container to the material. A part of this electrolyte flow is supplied as an etching liquid, e.g. by means of an electrolyte-conveying device, to the surfaces of the means of contact to be de-metalized and then flows outside the electroplating process electrolytic cell, intensively and in close proximity to these means of contact. This results in very low metalization, which might have been deposited on the contact wheel in the electrolytic cell at every rotation in spite of cooling and/or individual contact material, being immediately re-dissolved.

In addition to the intense flow of the etching electrolyte under considerable pressure, other physical and/or chemical devices or measures may be used to increase the effectiveness of this chemical etching of the surface of the means of contact:

-   -   The etch rate is substantially increased when this partial flow         of the electrolyte in this model is heated, for example, to 70°         C., i.e. well above the low working temperature in the working         container that is, for example, at 30° C.     -   The electrolyte that flows to the means of contact is enriched         with at least one oxidizing agent that is compatible with the         respective electrolyte of the electroplating process, such as         ozone, oxygen, air, atmospheric oxygen, hydrogen peroxide or         peracids.     -   Due to the ongoing consumption of chemicals and the dissipation         of electrolyte from the working container by the outgoing         material, the additives of the electrolyte must be replenished         continuously. Certain dosing agents may have etching properties         with respect to the deposited metalization. One example is the         chloride used in sulfuric acid copper baths for printed circuit         boards, and that can be injected, i.e. added in the form of a         salt to the electrolyte flowing to the means of contact.     -   Depending on the properties and the concentrations of the         additives in the electrolyte, the aforementioned measures to         increase the etching rate of the etching electrolyte that flows         to the means of contact can be combined with the cooling of         these means of contact.

When using insoluble anodes, the electrolyte must be continuously supplemented with the respective metal ions of the metal deposition or regenerated. This can be done by means of appropriate salts. A method that is described in the publication DD 215 589 A1 is also suitable for this purpose. A substance is added to the electrolyte in the form of an electrochemically reversible redox system. This substance or the redox agent is conveyed with the electrolyte through the working container and a regeneration chamber in the circuit. It is oxidized at the anode and again reduced in the regeneration area by electroless resolution dissolution of the regenerative metal. The metal dissolved in this way is deposited on the cathodic material in the electrolytic cell by means of an electroplating current source. An example of this is a sulfuric acid electrolyte, as used in printed circuit board production. Iron is used as a redox agent. In the working container and in the regeneration area, the following reactions essentially occur during these processes:

In the working container:

Anode: Fe²⁺−1e--->Fe³⁺

Cathode, material: Cu²⁺+2e--->Cu⁰

In the regeneration area: Cu⁰+Fe³⁺--->Cu²⁺+Fe²⁺

The oxidized redox agent at the insoluble anode, in this example iron, has Fe³⁺ as its ion, which has the ability to dissolve copper. This is used very advantageously in another model of the invention for the combined electroless dissolution of copper, which might still be deposited on the means of contact that are cooled according to the invention. To do this, a part of the electrolyte under circulation that is rich in Fe³⁺ is branched off from the area of the anode of the electrolytic cell and subject to intensive flow to the means of contact from where it would ideally be made to flow away from the surface of the material.

The invention will be described with reference to FIGS. 1 through 6 that are schematic and not to scale.

FIG. 1 shows two views of the situation for a first contact model for the one-sided contact of tape-shaped material with no rotating or sliding means of contact in a continuous flow system.

FIG. 2 shows a design of the electrical contact model of FIG. 1 in a side view as a section of a continuous flow system.

FIG. 3 shows two views of a second contact model, especially for plate-shaped material, with a rotating means of contact using rotary feed-throughs in a continuous flow system.

FIG. 4 shows two views of a third contact model especially for plate-shaped material with a rotating means of contact and a non-rotating cooling pipe in a continuous flow system.

FIG. 5 shows a side view of a continuous flow system with cooled means of contact in combination with electroless de-metalization of residual amounts of a possible metal deposition on these means of contact.

FIG. 6 a-c shows three views of a continuous flow system where the material is supplied through the working container as a rotating body on an electrically contacting slide rail.

In the first model of the invention, the cathodic means of contact are cooled to avoid contact metalization. In the second model of the invention, a contact material that is notmetalizable in the electrolyte is used.

The first model of the invention describes examples of tubular hollow bodies for the means of contact in continuous flow systems, which are traversed by a cooling medium. Especially in the case of the material to be electroplated that have a small width perpendicular to the direction of conveyance, other cooling methods can also be used advantageously, such as Peltier elements. In this case, a solid body consisting of a material offering good electrical and thermal conductivity such as copper can also be used as a means of contact. The cooling agent is then introduced from one or both sides of the means of contact.

In the second model of the invention with suitable materials on the surface of the means of contact, the cooling may in principle be done away with. In this case, no hollow bodies are necessary for the means of contact.

The third model of the invention is a combination of the first model of the invention with the second or the second model with the first. In all cases, the complete avoidance of any possible metalization of the means of contact can, if required, be achieved through additional electroless etching, i.e. chemical etching.

The invention is described with examples of continuous flow systems. It is also suitable for all other known plating systems such as immersion bath systems and drum systems.

FIG. 1 shows a first contact model, preferably for tape-shaped material 1, which is supplied through a continuous flow system. The material 1 is electroplated on one side only, in this case on the bottom. An example of material 1 would be RFID antennas mounted on a tape-shaped electrically insulating substrate that are supplied from roll to roll and are electroplated. The means of contact 6 on one of the numerous contact positions along the continuous flow system are arranged on the side that is to be electroplated of the material 1 in a static, i.e. non-rotating manner. The tape or substrate with the material 1 is drawn by at least one known winding device through the continuous flow system. It glides the structures over the sliding electrical contacts 6 while maintaining electrical contact. To support the tape conveyance, weight rollers 16 may be driven in a rotating manner along the upper side that is not to be plated. These weight rollers 16 should preferably have an electrically insulating material on their surface. This material may be hard or soft. On the one hand, this elasticity increases the length of the electrical contact on the weight rollers 16 in the direction of conveyance while, on the other hand, the weight rollers 16 reduce or avoid tensioning of the tape. Therefore, each driven weight roller 16 is effective in supplying the material 1 through the continuous flow system. Due to the greater contact area, the current density to the means of contact 6 is reduced, which reduces the possible wear of these means of contact 6.

It is possible to arrange the weight rollers 16 at the installation site to only rotate. According to a given number of means of contact 6 along the conveyance path of the continuous system, drawing rollers can be arranged on both sides to bear the advancement of the tape. The tape glides with the side to be contacted and electroplated over the statically arranged means of contact 6 that are formed in this model as hollow bodies.

According to the invention, a liquid or gaseous coolant 5 or cooling medium flows through the non-rotating tubular means of contact 6, which extend perpendicular to the direction of conveyance at least in part over the material 1. The coolant flow pipe 4 is flange-mounted directly on the means of contact 6. Similarly, the directly flange-mounted coolant return pipe 8 is located on the opposite side of the continuous flow system.

The working container 14 contains at least one soluble or insoluble anode 10, which together with the cathodically polarized surface of the material 1 forms the electrolytic cell 11. This electrolytic cell 11 contains the electrolyte 12, whose level 13 reaches at least as far up as the underside of the material 1. In this way, the electric field originating from the anode 10 is unable to reach the means of contact 6 as the latter is almost completely protected with electrical insulation 22. Only a small surface line, over which the substrate with the material 1 slides, is free from the insulation 22. This area can, however, be electroplated just like the material 1. In order to avoid this happening, the means of contact 6 are cooled in the first model of the invention. On a cathodic surface that has a much lower temperature than the working temperature of the electrolyte, no metal is deposited at least in the electrolytic baths, which are designed for a high working temperature. It is advantageous to have the greatest possible difference between the required working temperature of the electrolyte and the surface temperature of the means of contact 6. This is very often the case in practice. Tape-shaped material 1 can be electroplated at a low cost and with minimum maintenance with this extremely simple model of the invention. An otherwise very expensive de-metalization of the means of contact 6 is not required.

To achieve the necessary contact force between the material 1 and the means of contact 6, a certain angle of contact can also be selected. FIG. 1 shows a weight roller 16. This rests under its own weight on the tape-shaped material 1 and thus exerts the contact force on the means of contact 6 located across. This weight roller 16 is mounted to rotate and is caused to rotate by the tape or it may be rotated by the drive 3 to support the conveyance. The electrical conductors 23 connect the electrodes of the electrolytic cell with the plating rectifier(s).

FIG. 2 shows aside view of the situation of FIG. 1 with several means of contact 6 along the conveyance path of a continuous flow system. The insulation 22 on the cooled means of contact 6 almost reaches the material 1. In addition, the insulation 22 can rest firmly on the tubular means of contact 6. It not only acts as electrical insulation but also as thermal insulation for the flowing coolant 5. The cross-section of the hollow body of the means of contact may deviate from the circular shape shown, e.g. rectangular, preferably with the narrow side lying in the direction of conveyance so that the space thus obtained can be used for longer anodes 10 in the direction of conveyance. The electrically non-contacted weight rollers 16 can be driven as shown. Broken lines show an alternative arrangement of the driven weight rollers 16 between the means of contact 6, thereby also forming a wrap angle with the means of contact 6 with corresponding formation of contact force. The arrow 24 indicates the direction of conveyance.

The models of the invention according to the contact models illustrated in FIGS. 1 and 2 are suitable for frequent applications with tape-shaped material 1. These models are particularly cost-effective. For plate-shaped material 1, rotating wheels or rollers are usually required as means of contact 2, so that the latter can simultaneously act as conveyance means for the material 1. The other figures show these models.

In FIG. 3, the material 1 is electrochemically metalized only on the underside. The means of contact 2 shown have a tubular shape. They are mounted to rotate in the working container 14 and are rotated by the drive 3 as, for example, spur gears, whereby the material 1 are conveyed perpendicularly to the plane through the continuous flow system. Along the conveyance path, there are usually many such means of contact 2. The statically arranged coolant flow pipe 4 conveys the coolant 5 to a first rotary feed-through 7. From there, it flows through the tubular means of contact 2, whereby the surface of the means of contact 2 virtually assumes the temperature of the coolant 5. The coolant enters a statically arranged coolant return pipe 8 via a second rotary feed-through 7. The electrical current required for electroplating reaches the rotating means of contact 2 by means of an electrical conductor 23 and, for example, a sliding contact 9 or a rotating contact. The means of contact 2 rolls on the material 1, which can be plate-shaped or tape-shaped. In this way, the underside of the material 1 is contacted electrically. The material 1, together with the anode 10, forms the electrolytic cell 11. This is located in the electrolyte 12, whereby the level 13 in the working container 14 extends at least up to the material 1 to be coated. In this way, the means of contact 2 remain largely free of the electric field that originates from the anode 10, because there is a shielding 15 located above the metallic means of contact 2. This extends close to the surface of the material 1. This supports the non-metalization to be obtained by means of the means of contact 2. The known circulation elements necessary for electroplating for the electrolyte circulated are not shown in this and the other figures.

A specific contact force is required, among other things, for reliable electrical contact. This can be formed at the means of contact 2 in the case of tape-shaped material 1, for example, by forming a wrap angle. The figures in this description show how a contact force is produced by the weight rollers 16, which rest on the material 1 under their own weight. These weight rollers 16 can, for example, be driven to rotate by means of a belt drive or gear drive in order to support the conveyance of the material 1. In particular, in the case of tape-shaped material 1, it may be sufficient to have the weight rollers 16 simply rotating on the spot and not driven.

The side view of FIG. 3 shows section A-B. Here too, it can be seen that the model of the invention is simple to implement. Two rotary feed-throughs 7 are required for the contact model. However, they represent a significant cost factor as many means of contact 2 are required in a continuous flow system. This is, for example, the case when electrically insulating substrates have to be electroplated as plate-shaped structures that are insulated from each other and which have small dimensions in the direction of conveyance. An example of this is the electroplating of RFID antennas, which may be arranged on plates. The model of the invention according to FIG. 4 avoids the expense of rotary feed-throughs 7.

FIG. 4 shows a tube for the means of contact 2 in a tube model. The actual metallic means of contact 2 is again tubular. It is mounted to rotate in the working container 14. Another non-rotating cooling tube 17 is located in it to indirectly cool the means of contact 2. This is traversed by the coolant 5. The heat or cold exchange takes place from this heat pipe 17 to the tubular means of contact 2. By having a very small gap between the two tubes, a very small thermal resistance of the coolant with respect to the outer surface of the means of contact 2 is also achieved. In order to compensate for thermal expansion and tolerances, the cooling pipe 17 should preferably be connected to the coolant flow 4 by means of elastic sleeves 18 and to the coolant return pipe 8. Overall, this is an affordable and easy to assemble model of the invention.

FIG. 5 shows the combination of cooled means of contact 2 with or without almost non-metalized surfaces thereof and with chemical etching of possibly occurring residual metalization on the rotating means of contact 2. Several contact points along a continuous flow system are shown in the side view. The surface to be metalized on one side, such as structured RFID antennas 19, are located on an electrically non-conducting tape-shaped substrate 20. The distance between the means of contact 2 in the direction of conveyance should preferably be selected such that at least one means of contact is electrically in contact with each RFID antenna at all times. The supply and discharge of the coolant through the means of contact 2 are not shown in FIG. 5.

For any necessary supplementary chemical de-metalization, a chemically and/or physically conditioned etching liquid 27 flows against the means of contact 2 by means of an electrolyte supply device consisting of a an etching liquid pump and/or multi-way valves. This is done within the shielding 15, which also avoids spraying of the electrolyte when it flows at high pressure against the means of contact 2. The congruent openings 25 in the etching liquid pipe 21 as the circulation element and in the shielding 15 are arranged perpendicular to the direction of conveyance such that the entire surface of each means of contact 2 can be reached during rotation of the flowing electrolyte.

The other combination to avoid undesired metalization of the cathodic means of contact 2, 6 consists of the cooling thereof, and of selected materials or surfaces. In the case of certain electrolytic baths, little or no metal can be deposited on surfaces, which themselves consist of specially selected materials. If this material is used for the means of contact 2, 6 and for their surfaces, then these are not metalized or there is only moderate metalization. At least this supports the non-metalization of the means of contact, according to the invention. One example of this is, for example, a tin-plated surface on which hard chrome cannot be deposited, at least when there is a large difference between the working temperature of the electrolyte and the surface temperature of the means of contact 2, 6. The same applies to hard chromium electrolytes and means of contact, whose surface consists of niobium. Surfaces that are coated with electrically conducting diamond behave in a similarly selective manner. As a diamond layer is also very abrasion resistant, it is particularly suited for non-rotating means of contact 6 according to FIGS. 1 and 2

A printed image serves, for example, as an electrically conductive seed layer for structures to be electroplated on electrically non-conductive substrates. An electrically conductive printer paste, for example, is printed on the substrate by means of screen printing and cured.

This printed image, however, does not have very high abrasion resistance. Due to this, electrolytic strengthening using a device according to FIGS. 1 and 2, in which the printed image slides over the means of contact 6, could lead to the printed image being damaged in the seeding phase. In this case, the plating equipment according to FIGS. 3 to 5 is used for a short initial stretch at the beginning of electroplating. After protective initial metalization of the structures, additional reinforcement of the electroplating can be carried out using a device according to FIGS. 1 and 2. Overall, this is a very reliable and economical electroplating system by means of which the material can be produced very cost-effectively.

The models of the invention may also be designed as a mirror image, i.e. the top and bottom may be interchanged. In this case, the weight roller 16 is pressed on to the material 1. Part of the means of contact 2, 6 can then also be located outside of the electrolyte 12, i.e. above its level, which must at least reach the anodes 9. In the case of two-sided electroplating of the material, the devices according to the invention are interchanged above and underneath the material along the conveyance path.

FIG. 6 a-c shows an example of a continuous flow system for material. The material 1 are supplied through the working container 14 as statically arranged means of contact 6 serving as sliding or rotating conveyance supports. The means of contact 6 are protected against the electric field of the electrolytic cell 11 up to the area of the surface line 26 by means of insulation 22. The area on the surface line 26 in accordance with the invention is protected against undesired metalization by cooling the tubular means of contact 6 and/or by anon-metalizing surface in the electrolyte used. The coolant 5 flows through the means of contact 6. Insulation 22 also acts as a thermal insulator.

FIG. 6 a shows the cross-section of a continuous flow system according to the invention, with only an electrolytic cell 11 which is arranged in the lower region of the working container. It is formed from the material 1 and the cathodic anode 10. Both electrodes are located in the electrolyte 12, whose level 13 extends at least up to the material 1. The cathodic current supply to material 1 occurs via the electrical conductor 23 and via the means of contact 6 arranged along the conveyance path.

FIG. 6 b shows the top view of the arrangement in accordance with the invention. Only a short distance is shown in the direction of conveyance 24. In practice, such continuous flow systems are much longer to achieve a certain throughput, for example 5 meters. The means of contact 6 are arranged conically in the direction of conveyance in order to achieve an almost uniform deposition, even in the contact region. A very uniform coating thickness is achieved over the entire periphery of the material 1, for example piston rods for shock absorbers by the rotation of the material 1 during conveyance through the continuous flow system. This is also the case when even only one side of the material 1, as shown in the drawing, has one anode 10 and therefore also only one electrolytic cell 11.

FIG. 6 c shows the cross-section of a very short continuous flow system along the conveyance path as section C-D of FIG. 6 a. Electrolytic cells 11 are shown on the upper side and underneath. Thus, the deposition speed of the entire continuous flow system can be doubled. The drive required for the conveyance of the material 1, such as continuous and compressive tapes are known construction knowledge and, therefore, not shown in FIG. 6.

LIST OF REFERENCE NUMERALS

-   1 Material -   2 Rotary means of contact, contact wheel, contact roller, brush     contact -   3 Drive means -   4 Coolant flow -   5 Coolant -   6 Static means of contact, sliding contact, contact brush -   7 Rotary feed-through -   8 Coolant return pipe -   9 Sliding contact -   10 Anode -   11 Electrolytic cell -   12 Electrolyte -   13 Level -   14 Working container -   15 Shielding -   16 Weight roller -   17 Cooling pipe -   18 Cuff -   19 RFID antenna, material to be electroplated, material -   20 Substrate -   21 Etching liquid pipe -   22 Insulation -   23 Electrical conductor -   24 Arrow showing direction of conveyance -   25 Opening, nozzle -   26 Surface line -   27 Etching liquid, etching electrolyte 

1. Device for electrical contacting material to be electroplated (1) by means of contact (2,6) in electroplating systems of all kinds, whereby the cathodically polarized means of contact (2, 6) extend at least partially into the electrolyte (12) and electrically contact the material to be electroplated, characterized in that at least one of the means of contact (2, 6) can be cooled by means of a cooling device and/or a cooling medium.
 2. Device according to claim 1, characterized in that an electrically conductive surface of the means of contact (2, 6), which, for purposes of electrochemical deposition of metal, cannot, or can almost not, be metalized in the electrolyte (12).
 3. Device according to claim 1, characterized in that an electrolyte supply device supplies an etching liquid (27) to the means of contact (2), consisting of flow elements as etching liquid pipes (21) having openings or nozzles (25) as well as at least one etching liquid pump and/or multi-way valves.
 4. Method for electrically contacting the material to be electroplated (1) by means of means of contact (2, 6) in electroplating systems of all kinds, whereby the cathodically polarized means of contact (2, 6) extend at least partially into the electrolyte (12) and electrically contact the material to be electroplated, by using the device according to claim 1, characterized in that the means of contact (2, 6) can be cooled directly or indirectly by means of a cooling medium or a cooling device so that metalization of the means of contact (2, 6) on the surface thereof is avoided in the electrolyte (12) used.
 5. Method according to claim 4, characterized in that electrochemical metalization of the means of contact (2, 6) in the electrolyte (12) used is avoided by means of a repellent property of the material of the contacting surface of the means of contact (2, 6).
 6. Method according to claim 4, characterized in that permanent metalization of the means of contact (2) is avoided by chemically etching the surface of the means of contact (2) by means of a chemically and/or physically conditioned etching liquid (27).
 7. Device for electrically contacting the material to be electroplated (1) through the means of contact (2, 6) in electroplating systems of all kinds, whereby the cathodically polarized means of contact (2, 6) extend at least partially into the electrolyte (12) and electrically contact the material to be electroplated, characterized in that a substance of at least the contacting surface of the means of contact (2, 6) cannot, or can almost not, be electrochemically metalized in the electrolyte (12) used.
 8. Device according to claim 7, characterized in that the means of contact (2, 6) can be cooled by means of a cooling device and/or a cooling medium.
 9. Device according to claim 7, characterized in that an electrolyte supply device supplies an etching liquid (27) to the means of contact (2), consisting of flow elements as etching liquid pipes (21) having openings or nozzles (25) and at least one etching liquid pump and/or multi-way valves.
 10. Method for electrically contacting material to be electroplated (1) through the means of contact (2, 6) in electroplating systems of all kinds, whereby the cathodically polarized means of contact (2, 6) extend at least partially into the electrolyte (12) and electrically contact the material to be electroplated, by using the device according to claim 7, characterized in that the property of the material of the means of contact (2, 6) in the electrolyte (12) used keeps the surface thereof free or virtually free from electrochemical metalization.
 11. Method according to claim 10, characterized in that the means of contact (2, 6) can be cooled directly or indirectly by means of a cooling medium or a cooling device so that their surface is kept free or virtually free from electrochemical metalization in the electrolyte (12) used.
 12. Method according to claim 10, characterized in that permanent metalization of the means of contact (2) is avoided by chemically etching the surface of the means of contact (2) by means of a chemically and/or physically conditioned etching liquid (27). 